CARBON NITRIDE THIN-FILMS PREPARED BY REACTIVE SPUTTERING - ELEMENTALCOMPOSITION AND STRUCTURAL CHARACTERIZATION

Amorphous carbon nitride thin films (a-CNx) have been deposited onto S i(100) substrates by using a rf diode sputtering system. The films wer e deposited in reactive nitrogen-argon atmospheres. The partial pressu re of nitrogen ranged from 0% to 100% at two different deposition pres sures (Pd=2 Pa and P-d=8 Pa). The film composition was determined by i on beam techniques: Rutherford backscattering spectrometry and nuclear reaction analysis. The relative amount of carbon and nitrogen in the films is nearly independent of the nitrogen partial pressure in the re active plasma. The maximum nitrogen content is 48 at. %. The structura l characterization was performed by means of Raman and infrared spectr oscopies. Raman spectra revealed the presence of the D and G bands, ty pical of disordered carbon based materials, and a third band, at about 680 cm(-1), also attributed to film disorder. Infrared spectroscopy r esults showed the D and G Raman bands, IR allowed due to the nitrogen incorporation in the carbon network, the presence of a band at 2220 cm (-1) due to C=N bonds, and a broadband at 3300 cm(-1) that can be attr ibuted to the O-H stretching of water molecules absorbed in the films' voids. A linear correlation between the density and the internal stre ss of the films was also determined and the maximum values of the film density and the mechanical internal stress were measured for films de posited at 50% of nitrogen partial pressure (P-d=8 Pa). (C) 1997 Ameri can Vacuum Society.